A conventional cooling fan, either of the desktop or free standing type, oscillates in a generally horizontal plane to provide back-and-forth motion. This motion is achieved by a motor to drive the fan blades directly as well as to drive a gear train which causes rotation of an output shaft at a greatly reduced speed. The reduced speed output is typically used to drive a planar four-bar mechanism which generates the back-and forth motion of the fan head. Although this motion has some cooling benefit as compared to a non-oscillating fan, the motion can be improved.
Accordingly, there is a need to provide a fan structure which is capable of moving in three spatial planes to cause a fan head to move back-and-forth as well as up-and-down.